The present invention relates generally to gripper assemblies, and in particular to an industrial gripper assembly having an adjustable stroke.
In today""s automated manufacturing facility, it is customary to employ automated gripper assemblies to grasp a particular workpiece and transfer that workpiece to a new location where further processing can be conducted. These automated gripper assemblies are common place in industrial and manufacturing facilities, and are utilized to grasp a variety of industrial parts necessary for the manufacture of a particular device or component.
In many instances, a particular application requires the gripper assembly to grasp a workpiece located in an environment wherein there is only limited clearance for the gripper assembly to operate. That is, the jaws of the gripper assembly, when in the open position necessary to place the inner surfaces of the jaw about the exterior of the workpiece, must open only to a preselected angle so as to permit entrance or navigation about the environment in which the workpiece is located. Failure of the gripper assembly to operate within the limited clearance results in the inability of the gripper assembly to retrieve the object. Furthermore, if the angle at which the jaws are opened is greater than the clearance provided by the application, the jaws may contact the surrounding structure, often at enhanced speeds, and hence damage both the gripper assembly and surrounding structure.
In view of the space constraints placed upon a gripper assembly in many applications, the industry has advanced gripper assemblies having an adjustable stroke so as to enable adjustment of the angle or distance between the jaws when in the open position. However, these prior art adjustable stroke gripper assemblies are often complex and, as a result, relatively expensive. Furthermore, many of these prior art gripper assemblies require interchanging the jaw assembly to accommodate different clearance parameters. In most industrial applications, the gripper assembly will be required to transfer a variety of different workpieces located in different environments and having different clearance parameters. Thus, when there is a change in the workpiece to be transferred, or the environment in which it is positioned, it is often the case that the jaw assembly must be removed and a second jaw assembly inserted to thereby accommodate the different operating parameters. This jaw replacement procedure is cumbersome and often must be accomplished manually, and necessarily reduces the efficiency of the transfer process. Also, employing different jaw assemblies to accommodate different workpieces and their environments is relatively expensive and increases manufacturing costs. Moreover, repeatedly switching jaw assemblies tends to decrease the precision with which the transfer process is accomplished.
Consequently, there exists a need for an adjustable stroke gripper assembly which can be easily adjusted to accommodate different clearance requirements without replacing the jaw assembly.
Accordingly, the present invention provides a gripper assembly configured to adjustably alter the stroke of the jaw assembly, and thus alter angle defined by the jaws in the open position. Specifically, the gripper assembly is configured to permit the alteration of the jaw angle without having to replace the jaw assembly, and consequently, increases the efficiency and precision of the transfer process.
According to one aspect of the invention, a gripper assembly for use with a drive assembly having a drive member includes a housing connected to the drive assembly, and a jaw assembly carried by the housing and operably connected to the drive assembly. The jaw assembly includes a pair of jaws having at least a first open position and a second open position, each of which opens the pair of jaws to a different, preselected angle. A connection assembly operably connects the drive member to the pair of jaws. An adjustment member, carried by the housing, has a contact surface and is movable between at least a first and a second position, such that the pair of jaws open to a first open position and the connection assembly does not contact the contact surface when the adjustment member is in the first position, while the pair of jaws open to a second open position wherein the connection assembly contacts the contact surface when the adjustment member is in the second position. Providing an adjustment member carried by the housing of a gripper assembly for enabling the jaws of the housing to open to at least two distinct open positions, depending upon the position of the adjustment member, simplifies the transfer procedure, and enables different workpieces or parts to be effectively grasped in different clearance environments without switching the jaw assembly.
According to another aspect of the invention, a gripper assembly for use with a drive assembly having a drive member includes a pair of jaws attached to the housing and operably connected to the drive member by a connector member. An adjustment member, carried by the housing, has a stop surface selectively contacting the connector member such that when placed in a first position, the pair of jaws assume a first open position defining a first angle, whereas movement of the adjustment member into a second position results in contact between the connector member and the stop surface and permits the jaws to assume a second open position defining a second angle which not equal to the first angle. The second angle is determined by the spacing between the stop surface of the adjustment member and the drive assembly, and thus, permits the gripper assembly to assume any angular range required by the particular application.
According to still another aspect of the invention, a gripper assembly for use with a drive assembly having a drive member includes a housing connected to the drive assembly, and a pair of jaws carried by the housing, with at least one of the jaws pivotally attached to the housing. The jaws are operable between a closed position and at least one open position by movement of a connector member attached to the drive member and slidingly received by the housing. A pair of toggles are attached to the jaws and pivotally attached to the connector member. Sliding receipt of a connector member within the housing provides an effective and reliable structure for opening and closing the jaws of a gripper assembly.
According to still yet another aspect of the invention, a method for adjusting the stroke of a gripper assembly includes the step of providing an adjustment member having a preselected thickness and positioned between a drive assembly and the gripper assembly housing. The adjustment member is movable between at least a first and a second position, and when in the first position, enables the pair of jaws to open to a first open position, while movement to the second position opens the jaws to a second open position. Altering the position of an adjustment member to achieve different jaw angles reduces the manufacturing and operational complexity of the gripper assembly, thus reducing costs while increasing reliability. Further, employing an adjustment member capable of altering the stroke or jaw angle results in a gripper assembly capable of operating in various clearance environments without having to switch the jaws.
According to a further aspect of the invention, a gripper apparatus includes a housing, a jaw assembly carried by the housing and having a pair of jaws movable between a closed position and at least a first and a second open position. An adjustment member is attached to the housing and movable between at least a first position and a second position. The adjustment member is formed with a central cutout section or aperture, so that a drive member of a drive assembly extends through the cutout section and is operably connected to the pair of jaws. When the adjustment member is in the first position, and the drive member is in the retracted position, the jaws open to the first open position, while movement of the adjustment assembly to the second position results in the opening of the pair of jaws to the second open position. The gripper apparatus of the present invention which utilizes an adjustment member having a cutout section through which a drive member extends provides a reliable and effective structure to thereby increase or decrease the distance between the jaws in the open position.
According to an additional aspect of the invention, a gripper assembly for use with a drive assembly having a drive member includes a housing, a connector member movably positioned within the housing and operably connected to the drive member, and a toggle assembly pivotably connected to the connector member. A first jaw and a second jaw are rotatably attached to the housing and operably joined to the connector member by a toggle assembly. The connector member moves in the axis of travel with the drive member, and hence provides an efficient structure for opening and closing a pair of jaws.
These and other features and advantages of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification when read in conjunction with the accompanying drawings.